Fixed, Dynamic, Private or Public IP Addresses – How to define what your customer needs

By Anton Le Saux – 06/06/2017

One of the most popular topics I get asked about when discussing M2M solutions with Zest4 partners is IP addressing. Whilst most resellers understand what an IP address is, many resellers are not 100% clear on the difference between Fixed, Dynamic, Private and Public IP addresses and which should be used for different M2M devices.

Let me explain…

What is an IP Address?

First of all, let’s go back to basics and look at what an IP address actually is.

IP stands for ‘Internet Protocol’ and an IP address is basically a unique identity number for a piece of connected hardware. It allows a device to communicate with other devices (which will also have their own IP addresses too) over an IP-based network like the internet. But like most things in life, there are variations and these variations make a difference to how your connected device will work.

Dynamic vs Static IP Addresses

A Dynamic IP Address is the type that your network operator will usually issue with your mobile package and it’s dynamic because it changes each time a connection to the internet is made. This continuous change provides a good level of security and this type of IP address also generally costs less. The downside of a dynamic IP address, however, is that it can be more difficult to remotely access your device as there is no way of knowing what the IP address is going to be.

Completely the opposite to a dynamic IP address, a Static or Fixed IP Address is one that doesn’t change. This is a much better option for M2M and IoT applications as connected devices can communicate automatically without any human intervention and you can also remotely connect with your devices as the IP address will never change.

Public or Private IP Addresses?

Now that we’ve established that fixed IP addresses are best for M2M and IoT solutions, the next thing to understand is how the communication will take place and whether the fixed IP address needs a Private or Public profile.


A Fixed Private IP Address will always retain the same IP address but it will have a private profile that’s not hosted in the public domain. This means that the IP address is visible within your own network but it can’t be seen over the internet. This is great for devices that need to communicate with each other across an internal network, but to be able to remotely access connected devices over the web, a secure VPN would need to be in place.

The other option is a Fixed Public IP Address. As before, the IP address stays the same but it’s hosted in the public domain so it can be accessed over the Internet. This type of IP address needs to be provisioned by your supplier and, due a national shortage of available public IP addresses, they are chargeable. However, the cost is outweighed by the benefits of gaining full access to your connected devices from other devices or terminals, particularly for applications where remote access is critical, such as CCTV and digital signage.

How do I know which type of IP address is best for my customer?

The easiest way to establish which type of IP address is best for your customer is to understand what they want to achieve with their connected device. Here are a few example scenarios…

  1. If your customer doesn’t need to interact with their device, then a Dynamic IP Address would work.
  2. If your customer wants their devices to communicate independently and not rely on any human interaction with their internal network, then a Fixed Private IP Address would be the best solution.
  3. If the customer needs internal communication but with the ability to remotely access their devices for configuration purposes, for example, then a Fixed IP with a VPN would be required.
  4. If your customer needs full communication and access to devices over the Internet, then a Fixed Public IP Address would be the answer.How can Zest4 help with IP addressing?

Here at Zest4, we’re all about making life simple for our reseller partners and that’s no exception when it comes to IP addresses. All our managed data connections come with a Fixed Private IP address as standard or if their application demands, we can arrange a Fixed Public IP address for a minimal additional charge. We can also set up a secure VPN for your customer via an SSL connection or IPSec and customers will have full visibility of their SIM estate via our secure managed portal.


If you’re still not sure about IP addressing and would like some more information and advice, give myself and the Zest4 team a call on 0161 956 3355 or visit